Multi-speed transmission

ABSTRACT

A multi-speed transmission with six forward gears and one reverse gear having an input and output shaft, three planetary gear sets (P 1,  P 2,  P 3 ), six rotatable shafts and five control elements. The input shaft communicates with the gear set (P 2 ), the shaft ( 3 ), and the shaft ( 4 ). The shaft ( 3 ) communicates with the carrier of the gear set (P 1 ), the housing and the shaft ( 6 ). The shaft ( 4 ) communicates with the gear set (P 1 ) and the housing. The shaft ( 5 ) communicates with the gear set (P 1 ) and the gear set (P 3 ). The shaft ( 6 ) communicates with the gear set (P 2 ). The output shaft communicates with the gear set (P 3 ) and the gear set (P 2 ), and the gear set (P 3 ) communicates with the housing.

This application claims priority from German Application Serial No. 102006 006 616.2 filed Feb. 14, 2006.

FIELD OF THE INVENTION

The present invention relates to a multi-speed transmission in planetarydesign, particularly an automatic transmission for a motor vehicle.

BACKGROUND OF THE INVENTION

According to the state of the art, automatic transmissions, particularlyfor motor vehicles, comprise planetary gear sets, which are shiftedusing friction and/or control elements, such as clutches and brakes, andwhich are typically connected to a starting element that is subject to aslip effect and optionally provided with a converter lock-up clutch, forexample a hydrodynamic torque converter or a fluid clutch.

A transmission of this type is described in EP 0 434 525 A1. Itcomprises substantially one input shaft and one output shaft, which aredisposed parallel to each other, a double planetary gear set concentricwith the output shaft, and five control elements in the form of threeclutches and two brakes, the selective operation of which, in pairs,determines the different gear ratios between the input shaft and theoutput shaft. This transmission has a front-mounted gear set and twopower paths, so that by the selective engagement, in pairs, of the fivecontrol elements, six forward gears are obtained.

In the first power path, two clutches are required for transmitting thetorque from the front-mounted gear set to two elements of the doubleplanetary gear set. These elements are provided in the power flowdirection substantially behind the front-mounted gear set in thedirection of the double planetary gear set. In the second power path, afurther clutch is provided, which detachably connects this path with afurther element of the double planetary gear set. The clutches aredisposed such that the inner disk carrier forms the output end.

Furthermore, from the published prior art document U.S. Pat. No.6,139,463 a compact multi-speed transmission in planetary design,particularly for a motor vehicle, is known, which has two planetary gearsets and one front-mounted gear set, as well as three clutches and twobrakes. In this known multi-speed transmission, two clutches C-1 and C-3are provided in a first power path for transmitting the torque from thefront-mounted gear set to the two planetary gear sets. The outer diskcarrier and/or the cylinder or piston and pressure compensation sides ofthe clutch C-3 are connected with a first brake B-1. Furthermore, theinner disk carrier of the third clutch C-3 is connected to the cylinderand/or piston and pressure compensation sides of the first clutch C-1,the inner disk carrier of the first clutch C-1 being disposed on theoutput side and connected to a sun gear of the third planetary gear set.

From DE 199 49 507 A1 by the applicant, a multi-speed transmission isalso known, according to which on the drive shaft two non-shiftable,front-mounted gear sets are provided, which on the output side generatetwo rotational speeds which, in addition to the rotational speed of theinput shaft, can be switched by selectively engaging the controlelements to a shiftable double planetary gear set that acts upon theoutput shaft, such that, for changing from one gear to the next higheror lower gear, only one of the two actuated control elements must beengaged or disengaged.

DE 199 12 480 A1 discloses an automatically shiftable motor vehicletransmission with three carrier-mounted planetary gear sets as well asthree brakes and two clutches for switching between six forward gearsand one reverse gear, and with one drive shaft and one output shaft. Theautomatically shiftable motor vehicle transmission is configured suchthat the drive shaft is directly connected to the sun gear of the secondplanetary gear set, and the drive shaft can be connected via the firstclutch to the sun gear of the first planetary gear set and/or via thesecond clutch to the carrier of the first planetary gear set.Additionally or alternatively, the sun gear of the first planetary gearset can be connected via the first brake to the transmission housingand/or the carrier of the first planetary gear set can be connected viathe second brake to the housing and/or the sun gear of the thirdplanetary gear set can be connected via the third brake to the housing.

Furthermore, DE 102 13 820 A1 discloses a multi-speed automatictransmission comprising a first input path T1 of a first speed ratio, aninput path T2, which has a larger speed ratio than the input path T1, aplanetary gear set with four elements, wherein the four elements arearranged in order of the direction of power flow a first element, asecond element, a third element and a fourth element, a clutch C-2 thattransmits a rotation from the input path T2 to the first element S3, aclutch C-1 that transmits the rotation from the input path T2 to thefourth element S2, a clutch C4 that transmits a rotation from the inputpath T1 to the first element, a clutch C-3 that transmits the rotationfrom the input path T1 to the second element C3, a brake B-1 thatengages the fourth element, a brake B-2 that engages the second element,and an output member that is coupled with the third element R3.

Within the scope of DE 101 15 983 A1 by the applicant, a multi-speedtransmission is described, comprising a drive shaft that is linked witha front-mounted gear set, an output shaft that is connected with arear-mounted gear set, and a maximum of seven control elements, throughthe selective shifting of which at least seven forward gears can beshifted without range shifting. The front-mounted gear set is formed bya front-mounted planetary gear set or a maximum of two non-shiftablefront-mounted planetary gear sets that are linked with the firstfront-mounted planetary gear set, wherein the rear-mounted gear set isconfigured as a two-carrier four-shaft transmission with two shiftablerear-mounted planetary gear sets, and has four free shafts. The firstfree shaft of this two-carrier four-shaft transmission is connected withthe first control element, the second free shaft with the second andthird control elements, the third free shaft with the fourth and fifthcontrol elements, and the fourth free shaft is connected with the outputshaft. According to that invention, a multi-speed transmission with atotal of six control elements is proposed, which connect the third freeshaft or the first free shaft of the rear-mounted gear set additionallywith a sixth shifting element. For a multi-speed transmission with atotal of seven control elements, it is proposed according to thatinvention that the third free shaft is additionally connected with asixth control element D′, and the first free shaft is additionallyconnected with a seventh control element.

Furthermore, the scope of DE 101 15 987 by the applicant describes amulti-speed transmission with at least seven gears. In addition to theinput shaft and the output shaft, this transmission comprises anon-shiftable front-mounted gear set and a shiftable rear-mounted gearset in the form of a two-carrier four-shaft transmission. Thefront-mounted gear set comprises a first planetary gear set, which, inaddition to the input rotational speed of the input shaft, also providesa second rotational speed, which may optionally be shifted to arear-mounted gear set. The rear-mounted gear set comprises two shiftableplanetary gear sets, which can shift at least seven gears using the sixshift elements, forming two power paths. During each shifting operation,range shifting is advantageously avoided. A 9-gear multi-speedtransmission is further known from DE 29 36 969; it comprises eightcontrol elements and four gear sets.

Automatic vehicle transmissions in planetary design in general havepreviously been described in the prior art on many occasions and undergocontinuous developments and improvements. These transmissions shouldhave, for example, a sufficient number of forward gears as well as onereverse gear and a gear ratio spread that is excellently suited formotor vehicles, having a high overall spread as well as favorableprogressive ratios. Furthermore, they should allow a high starting gearratio in the forward direction and should include a direct gear, andadditionally should be suited for use both in passenger cars and incommercial vehicles. In addition, these transmissions should have a lowcomplexity, in particular they should require a small number of controlelements, and should avoid double-shifts when shifting sequentially, sothat always only one control element is engaged when shifting in definedgear groups.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to propose amulti-speed transmission of the type mentioned above in which the designcomplexity is optimized and furthermore the efficiency in the maindriving gears in terms of drag and gearing losses is improved.Furthermore, it is intended that low torque act on the control elementsand planetary gear sets in the multi-speed transmission according to theinvention, and that the rotational speeds of the shafts, controlelements and planetary gear sets be kept as low as possible. Inaddition, the required number of gears and the spread of the gear ratiosare also supposed to be maintained, advantageously implementing sixforward gears and at least one reverse gear. Furthermore, thetransmission according to the invention is supposed to be suitable forany design in a vehicle, particularly for a frontal-transverseconfiguration.

According to the invention, a multi-speed transmission in planetarydesign is proposed, which has one input shaft and one output shaft,which are disposed in a housing. Furthermore, at least three planetarygear sets—hereinafter referred to as the first, second and thirdplanetary gear sets—, at least six rotatable shafts—hereinafter referredto as the input shaft, output shaft, third, fourth, fifth and sixthshafts—and at least five control elements, comprising brakes andclutches, are provided; the selective engagement of these componentscreates different gear ratios between the input shaft and the outputshaft, so that preferably six forward gears and one reverse gear can beshifted.

The input shaft is permanently connected to the sun gear of the secondplanetary gear set, it can be detachably connected via a clutch to thethird shaft and via a further clutch to the fourth shaft, wherein thethird shaft is permanently connected to the carrier of the firstplanetary gear set, can be coupled to the housing via a brake, and canbe detachably connected to the sixth shaft via a clutch, wherein thefourth shaft is permanently connected to the sun gear of the firstplanetary gear set and can be coupled to the housing via a brake.

Furthermore, the fifth shaft is permanently connected to the ring gearof the first planetary gear set and to the carrier of the thirdplanetary gear set, wherein the sixth shaft is permanently connected tothe ring gear of the second planetary gear set.

According to the invention, the output shaft is permanently connected tothe ring gear of the third planetary gear set and to the carrier of thesecond planetary gear set, wherein the sun gear of the third planetarygear set is non-rotatably connected to the housing via a non-rotatingshaft.

The configuration of the multi-speed transmission according to theinvention produces suitable gear ratios, particularly for passengercars, as well as a considerable increase in the total spread of ratiosof the multi-speed transmission, resulting in improved driving comfortand a significant improvement in fuel economy.

In addition, the multi-speed transmission according to the inventionallows a considerably decreased complexity to be achieved, due to thelow number of control elements, preferably two brakes and threeclutches. It is advantageously possible with the multi-speedtransmission according to the invention to start driving with ahydrodynamic converter, a hydrodynamic clutch, an external startingclutch or other suitable external starting elements. It is alsoconceivable to allow a starting operation with a starting element thatis integrated into the transmission. A control element, which isactuated in the first gear and in the reverse gear, is preferred.

In addition, good efficiency in the main driving gears with regard todrag and gearing losses can be achieved with the multi-speedtransmission according to the invention.

Furthermore, low torque is present in the control elements and in theplanetary gear sets of the multi-speed transmission, thus advantageouslyreducing the wear on the multi-speed transmission. In addition, the lowtorque makes correspondingly small dimensions possible, allowingreductions in the required installation space and the correspondingexpenses. Also, the rotational speeds in the shafts, control elementsand planetary gear sets are low.

In addition, the transmission according to the invention is designedsuch that it can be adjusted to different drive train configurations,both in the power flow direction and with regard to space.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail hereinafter withreference to the exemplary embodiments in the figures, wherein:

FIG. 1 is a schematic illustration of a preferred embodiment of amulti-speed transmission according to the invention; and

FIG. 2 is an exemplary shifting pattern for the multi-speed transmissionaccording to the invention from FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a multi-speed transmission according to the inventioncomprising an input shaft 1 (An) and an output shaft 2 (Ab), which aredisposed in a housing G. Three planetary gear sets P1, P2, P3 areprovided, which are preferably configured as negative planetary gearsets and are disposed in the sequence P1, P2, P3 in the axial direction(and also in the power flow direction).

As can be seen from FIG. 1, only five control elements, namely twobrakes 03, 04 and three clutches 13, 14, and 36, are provided. Withthese control elements, a selective engagement of preferably six forwardgears and one reverse gear can be implemented. The multi-speedtransmission according to the invention has a total of six rotatableshafts, namely the shafts 1, 2, 3, 4, 5 and 6.

According to the invention, it is provided on the multi-speedtransmission according to FIG. 1 that the input occurs via the shaft 1,which is permanently connected to the sun gear of the second planetarygear set P2, can be detachably connected via a clutch 13 to the shaft 3and via a clutch 14 to the shaft 4, wherein the shaft 3 is permanentlyconnected to the carrier of the first planetary gear set P1, can becoupled to the housing G via the brake 03, and is detachably connectedto the shaft 6 via the clutch 36, wherein the shaft 4 is permanentlyconnected to the sun gear of the first planetary gear set P1 and can becoupled to the housing G via the brake 04.

Furthermore, the shaft 5 is permanently connected to the ring gear ofthe first planetary gear set P1 and to the carrier of the thirdplanetary gear set P3, wherein the shaft 6 is permanently connected tothe ring gear of the second planetary gear set P2.

The output occurs via the shaft 2, which is permanently connected to thering gear of the third planetary gear set P3 and to the carrier of thesecond planetary gear set P2. Furthermore, the sun gear of the thirdplanetary gear set P3 is non-rotatably connected to the housing G viathe shaft 0.

Within the scope of the illustrated embodiments, the clutches 13 and 14are disposed in front of the first planetary gear set P1 in the sequence13, 14 from an axial point of view in the power flow direction, and maycomprise a common outer disk carrier as disk clutches. The brakes 04, 03are also disposed in front of the first planetary gear set P1 in thesequence 04, 03, from an axial point of view in the power flowdirection.

The spatial configuration of the control elements is optional and islimited only by its dimension and outer shape.

FIG. 2 shows a shifting pattern of the multi-speed transmission of theinvention according to FIG. 1 by way of example. For each gear, twocontrol elements are engaged. The shifting pattern shows the respectivegear ratios i of the individual gear steps and the resulting progressiveratios phi by way of example. Typical stationary gear ratio values forthe planetary gear sets P1, P2, P3 are −3.250, −2.282 and −2.480,respectively. The shifting pattern also shows that double-shifts and/orrange shifts are avoided when shifting sequentially because twoadjoining gear steps jointly use one control element. It is preferableif the fourth gear is configured as a direct gear.

The first gear is defined by engaging the brake 03 and the clutch 36,the second gear by engaging the brake 04 and the clutch 36, and thethird gear is defined by engaging the clutches 14 and 36. Furthermore,the fourth gear is defined by engaging the clutch 13 and the clutch 36,the fifth gear by engaging the clutches 13 and 14, and the sixth gear byengaging the brake 04 and the clutch 13. As the shifting pattern shows,the reverse gear is defined by engaging the brake 03 and the clutch 14.

According to the invention, initiating driver with an integrated controlelement 03, 36 is possible (IAK), for which particularly the brake 03 issuited, which is required in the first gear and the reverse gear.Furthermore, depending on the shifting logic, different gear steps maybe obtained from the same gear pattern, allowing application- and/orvehicle-specific variations.

In addition, as shown in FIG. 3, it is possible to provide additionalone-way clutches 38 in suitable locations of the multi-speedtransmission, for example between a shaft and the housing, or tooptionally connect two shafts.

On the input side or on the output side, an axle differential 20 and/ora transfer case may be provided according to the invention, shown inFIG. 8.

Within the scope of an advantageous further development, as shown inFIG. 9, the input shaft 1 may be separated from a driving motor 30 asneeded by a coupling element 24, wherein the coupling element 24 may bea hydrodynamic converter, a hydraulic clutch, a dry starting clutch, awet starting clutch, a magnetic powder clutch or a centrifugal clutch.It is also possible, as shown in FIG. 7, to provide such a drivingelement 25 in the power flow direction behind the transmission, whereinin this case, as seen in FIG. 10, the input shaft 1 is permanentlyconnected to the crankshaft 32 of the drive motor 30.

The multi-speed transmission according to the invention, shown in FIG.11, also allows the provision of a torsional vibration damper 34 betweenthe drive motor 30 and the transmission.

Within the scope of a further embodiment of the invention, shown in FIG.5, a wear-free brake 42, such as a hydraulic or electric retarder or thelike, may be provided on each shaft, preferably on the input shaft 1 orthe output shaft 2, which is particularly important when thetransmission is used in commercial vehicles. Furthermore, as shown inFIG. 12, a power take-off 44 may be provided on each shaft, preferablyon the input shaft 1 or the output shaft 2, to drive additional units36.

Additionally, as shown in FIG. 6, the input and output shafts areprovided on the same side of the housing. The control elements that areused may be configured as power-shift clutches or brakes. In particular,power-shift clutches or brakes such as multi-disk clutches, band brakesand/or cone clutches, may be used. Furthermore, it is also possible touse positive brakes and/or clutches, such as synchronization devices orclaw clutches, as the control elements.

A further advantage of the multi-speed transmission presented and shownin FIG. 4 here is that an electric machine 40 can be provided on eachshaft as a generator and/or as an additional drive unit 36.

Of course, any design configuration, particularly any spatialconfiguration of the planetary gear sets and the control elements assuch as well as in relation to each other, to the extent they aretechnically expedient, falls under the scope of protection of thepresent claims, without influencing the function of the transmission asdescribed in the claims, even if these embodiments are not explicitlyillustrated in the figures or mentioned in the description.

REFERENCE SYMBOLS

-   0 Shaft-   1 Shaft-   2 Shaft-   3 Shaft-   4 Shaft-   5 Shaft-   6 Shaft-   03 Brake-   04 Brake-   13 Clutch-   14 Clutch-   36 Clutch-   P1 Planetary gear set-   P2 Planetary gear set-   P3 Planetary gear set-   An Input-   Ab Output-   i Gear ratio-   phi Progressive ratio-   G Housing

1-24. (canceled)
 25. A multi-speed transmission of a planetary designfor an automatic transmission of a motor vehicle, the transmissioncomprising: an input shaft (1) and an output shaft (2) arranged in ahousing (G); first, second, and third planetary gear sets (P1, P2, P3),and each of the first, the second, and the third planetary gear sets(P1, P2, P3) comprising, a sun gear, a carrier, and a ring gear; atleast third, fourth, fifth and sixth rotatable shafts (3, 4, 5, 6), aswell as at least five control elements (03, 04, 13, 14, 36) comprisingfirst and second brakes (03, 04) and first, second and third clutches(13, 14, 36) whose selective engagement creates different gear ratiosbetween the input shaft (1) and the output shaft (2) so that at leastfirst, second, third, fourth, fifth and sixth forward gears and onereverse gear are implemented; wherein the input shaft (1) is permanentlyconnected to the sun gear of the second planetary gear set (P2) and iscouplable, via the first clutch (13), to the third shaft (3) and theinput shaft (1) is couplable, via the second clutch (14), to the fourthshaft (4); the third shaft (3) is permanently connected to the carrierof the first planetary gear set (P1) and the third shaft (3) iscouplable, via the first brake (03), to the housing (G) and iscouplable, via the third clutch (36), to the sixth shaft (6); the fourthshaft (4) is permanently connected to the sun gear of the firstplanetary gear set (P1) and is couplable, via the second brake (04), tothe housing (G); the fifth shaft (5) is permanently connected to theinternal gear of the first planetary gear set (P1) and the carrier ofthe third planetary gear set (P3); the sixth shaft (6) is permanentlyconnected to the internal gear of the second planetary gear set (P2);the output shaft (2) is permanently connected to the internal gear ofthe third planetary gear set (P3) and the carrier of the secondplanetary gear set (P2); and the sun gear of the third planetary gearset (P3) fixed, via a seventh shaft (0), to the housing (G).
 26. Themulti-speed transmission according to claim 25, wherein the first, thesecond and the third planetary gear sets (P1, P2, P3) are arranged, in adirection of power flow, in the sequential order of: the first planetarygear set (P1), the second planetary gear set (P2) and the thirdplanetary gear set (P3).
 27. The multi-speed transmission according toclaim 25, wherein the first, the second and the third planetary gearsets (P1, P2, P3) are negative planetary gear sets.
 28. The multi-speedtransmission according to claim 25, wherein the first and the secondclutches (13, 14) are arranged, in the direction of power flow, in frontof the first planetary gear set (P1) and in the sequential order of: thefirst clutch (13) and the second clutch (14).
 29. The multi-speedtransmission according to claim 25, wherein the first and the secondclutches (13, 14) are multi-disk clutches which have a common outerdisk.
 30. The multi-speed transmission according to claim 25, whereinthe first and the second brakes (03, 04) are arranged, in the directionof power flow, in front of the first planetary gear set (P1) and in thesequential order of: the second brake (04) and the first brake (03). 31.The multi-speed transmission according to claim 25, wherein the firstgear results from engagement of the first brake (03) and the thirdclutch (36), the second gear results from engagement of the second brake(04) and the third clutch (36), the third gear results from engagementof the second and the third clutches (14, 36), the fourth gear resultsfrom engagement of the first and the third clutches (13, 36), the fifthgear results from engagement of the first and second clutches (13, 14),and the sixth gear results from engagement of the second brake (04) andthe first clutch (13).
 32. The multi-speed transmission according toclaim 25, wherein the reverse gear results from engagement of the firstbrake (03) and the second clutch (14).
 33. The multi-speed transmissionaccording to claim 25, wherein at least one one-way clutch is providedin the transmission.
 34. The multi-speed transmission according to claim33, wherein the one-way clutch is provided between at least one of theinput shaft (1), the output shaft (2), the third shaft (3), the fourthshaft (4), the fifth shaft (5) and the sixth shaft (6) and the housing(G).
 35. The multi-speed transmission according to claim 25, wherein theinput and the output shafts (1, 2) are located on a common side of thehousing (G).
 36. The multi-speed transmission according to claim 25,wherein one of an axle differential and a transfer case is provided onone of an input side and output side of the transmission.
 37. Themulti-speed transmission according to claim 25, wherein a couplingelement facilitates separation of the input shaft (1) from a drivemotor.
 38. The multi-speed transmission according to claim 37, whereinthe coupling element is one of a hydrodynamic converter, a hydraulicclutch, a dry starting clutch, a wet starting clutch, a magnetic powderclutch, and a centrifugal clutch.
 39. The multi-speed transmissionaccording to claim 25, wherein an external driving element is arrange,in the direct of power flow, downstream of the transmission and theinput shaft (1) is firmly connected to a crankshaft of a drive motor.40. The multi-speed transmission according to claim 25, wherein staringof the transmission occurs by engagement of one of the first brake (03)and the third clutch (36), and the input shaft (1) is permanentlyconnected to a crankshaft of a drive motor.
 41. The multi-speedtransmission according to claim 25, wherein a torsional vibration damperis arranged between a drive motor and the transmission.
 42. Themulti-speed transmission according to claim 25, wherein a wear-freebrake is arranged on at least one of the input shaft (1), the outputshaft (2),the third shaft (3), the fourth shaft (4), the fifth shaft (5)and the sixth shaft (6).
 43. The multi-speed transmission according toclaim 25, wherein a power take-off is arranged on at least one of theinput shaft (1), the output shaft (2), the third shaft (3), the fourthshaft (4), the fifth shaft (5) and the sixth shaft (6) for driving anadditional unit.
 44. The multi-speed transmission according to claim 43,wherein the power take-off is arranged on one of the input shaft (1) andthe output shaft (2).
 45. The multi-speed transmission according toclaim 25, wherein each of the five control elements (03, 04, 13, 14, 36)is one of a power-shift clutch and a power-shift brake.
 46. Themulti-speed transmission according to claim 45, wherein each of the fivecontrol elements (03, 04, 13, 14, 36) is one of a multi-disk clutch, aband brake, and a cone clutch.
 47. The multi-speed transmissionaccording to claim 25, wherein each of the five control elements (03,04,13,14, 36) is one of a positive brake and a clutch.
 48. Themulti-speed transmission according to claim 25, wherein an electricmachine is arranged on at least one of the input shaft (1), the outputshaft (2), the third shaft (3), the fourth shaft (4), the fifth shaft(5) and the sixth shaft (6) as one of a generator and an additionaldriving unit.